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RE: 7N7 & 7AF7: what were they designed for and when were they used?

Posted by Swanson (A) on January 17, 2008 at 17:53:48

In Reply to: 7N7 & 7AF7: what were they designed for and when were they used? posted by Frihed89 on January 17, 2008 at 12:39:40:

Loktal tubes were invented by Sylvania in the late 1930's.
One of the origional applications was computer use.They
also wanted to be different from RCA and come out with a range
of tubes with a unique base.Back then nobody wanted to pay
RCA royalties and it also meant Sylvania would have a captive
audience once a manufacturer decided to use the loktal tubes.Motorola
liked to use them in their car radios and mobile FM communications
equipment.Zenith and Philco were fond of them and used them in
their consumer radios.They were overkill in this application
but Zenith and Philco would do anything not to use RCA octal
tubes.Those companies did not get along too well with each
other.Of course,WW2 started and loktal found their most famous
application in military equipment especially in airplanes.
The famous Setchell-Carlson BC-1206 aircraft beacon receiver
used 5 loktal tubes packed into a tight chassis.Unfortunately
most people did/do not know how to remove and insert these tubes
properly into their sockets so many of the sockets were ruined.
These tubes were very popular with homebrewers back in the 50's
because they were cheap on the surplus market and so were the
sockets.Fast forward to today,and unfortunately loktal sockets
have become rather scarce so the sockets and the tubes have become
rather pricey.
Regards,
Swanson

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